The present invention relates to the milling of grain and more particularly to the production of farina.
Farina, as defined by U.S. government standards, is the food prepared by grinding and bolting cleaned wheat, other than durum and red durum wheat, to such fineness that it passes through a No. 20 U.S. standard sieve but not more than 3 percent passes through a No. 100 U.S. standard sieve. Farina is normally produced as a co-product of flour milling. In the conventional flour mill, the wheat is passed through a series of breaking and reduction operations designed to rapidly reduce the endosperm portion of the wheat berry to flour. The breaking operations typically include up to five roller milling units and the output of each unit is classified by size. A certain amount of flour is produced at each break and that is separated from the larger particles by bolting. The largest particles are directed to the next break roll, while the intermediate size particles (which include those of farina size) are air purified to remove bran particles and are passed to reduction roller mill units to be ground into flour. In the conventional flour mill a considerable portion of the output of the breaking operations in fine farina, and the mill operators can elect to extract a portion of this farina for use as hot breakfast cereal rather than use it to produce flour.
Most farina sold as hot breakfast cereal contains a high percentage of fine farina, i.e. particles which will pass through a No. 40 U.S. standard sieve. There is, however, a popular hot breakfast cereal product composed predominately of coarse farina particles of a size too large to pass through a No. 40 standard sieve. The conventional flour mill produces a very small amount of farina in the No. 20 to No. 40 standard sieve size. Therefore, in order to obtain a sufficient quantity of coarse farina to nationally market a popular breakfast cereal, it is necessary to purchase coarse farina from a large number of flour mills when and where it is available. Since flour mills differ in the way they grind, classify and purify their stock it is necessary to carefully blend the farina from various sources in order to provide a high quality and uniform product.